Solar thermal tubes like these tap the heat of the sun to provide warmer air to HVAC systems, reducing the energy needed to heat buildings.
Solar thermal energy, which involves the heating of water through solar collectors, can be used to supplement the energy efficiency of a building’s existing HVAC system, or as part of a new hybrid geothermal/solar system. Separate from Ameresco’s capabilities in photovoltaics, which convert solar energy directly into electricity, our solar thermal projects make better use of the heat that the sun freely supplies to buildings.
Ameresco finances, designs, builds, operates and maintains solar thermal systems as part of a broader energy management approach that is focused on cost savings through energy efficiency. Solar thermal collectors, installed on-site and often placed on the roofs or walls of commercial buildings, collect solar heat that is used for heating, cooling and hot water. When solar thermal is used to supplement geothermal as a hybrid system, organizations can often cover 100% of these HVAC functions with clean, renewable energy.
Passive Solar Heat
In additional to solar thermal systems, which are active mechanical systems, Ameresco can ensure that facilities are maximizing their use of solar heat by passively utilizing the direct radiation on a building’s structure. Ameresco’s experienced energy services engineers can design buildings to capture more of the sun’s radiation, and building materials can be chosen to absorb and retain the heat, slowly releasing it at night or on cooler days.
Creating a Passive Solar “Chimney”
Each day, a building gains a portion of its heat just from sunlight hitting its exterior. By creating a passive solar “chimney,” buildings can retain or expel more of this heat as needed. The solar chimney is designed with a sun-penetrating glass shield on a southerly or westerly-facing solid wall, with a cavity several inches deep between the layers. With the sun’s heat concentrated between the glass shield and the wall, a convection of rising heat is created, which is captured by a heat-recovery ventilator (HRV) at the top, which then circulates the heat into the building on cool days and expels it upward on warm days.
Featured Case Study
Arizona State University
A solar thermal system was installed on Sun Devils Stadium at Arizona State University, part of a campus-wide renewable energy program that saves $8 million annually in energy costs.